COMANCHE TECH TALK
TRIM TAB TRAUMA
by Ben Ayalon
It was late August - early September 2002 when my wife, Sue, and I arrived at our home airfield on our way to the European fly-in and tribe annual general meeting in Vannes, France. To save time, the customs form and flight plan had been submitted on the previous day. The walk-around was conducted and we boarded N9381P, our trusty PA24-260-C. On our flight, we had to negotiate low clouds over parts of the UK, and there were some stressful moments inside the clouds. We spent a lovely weekend in Vannes, and only too soon it was time to fly back home. The coach took us back to the Vannes airport; we said our goodbyes and departed for Elstree, England, our home base.
Immediately after rotation, a sharp avoidance maneuver had to be taken due to a parachute descending (or a weather balloon) over the runwaycenter line. I informed the tower, and following our departure, asked to hold until it was checked out. Fortunately, the airplane flew normally.
We had decided to land at Jersey, one of the English Channel Islands for cheap fuel before continuing home. Whilst over the English Channel, and 20 minutes from land, our alternator ceased working. We informed both French and British control that we would be out of radio contact as we were forced to turn all power off to preserve our battery so we could lower the gear and the flaps later on. Upon arrival at the airport entry point I turned the battery power on and contacted the airport. The radar unit that had followed us all the way had already informed them of our situation and they were waiting for us. We landed safely and were met by the crash team who were waiting near the touchdown point. I was happy that the battery lasted and that there was no need to do an emergency gear extension. It was crucial to have enough power to enable us to lower our landing gear and flaps. Our home airfield has a short runway with trees on the approach, hence a flap-less landing is out of the question.
We taxied to parking, being escorted by an emergency vehicle, and turned the engine off. The airport chap jumped out of his vehicle and shouted, "Ben, I will give you a push". I said, "Please." and the aircraft started to roll backwards. BANG! The unmistakable sound of bad news was heard from the back.
The aircraft had been pushed into the bushes behind, damaging the left stabilator trim tab and causing a ripple on the right stabilator. The following day my maintenance shop had a look and said that they would not be able to handle the repair work due to lack of suitable equipment Their advice was to find a second-hand trim tab, as the cost of repair would be very high. Calls to various U.S. sources which deal in Comanche parts produced no results. Trim tabs or skins were not available. The only way forward was to move the aircraft to a shop that could do the repair work to a very high standard. After a further inspection I was told that the aircraft was safe to fly and I flew it very gingerly to Marshall Aerospace which is based at, and is the owner of, Cambridge airport. Regardless of being the European service center for Lockheed, Marshall Aerospace is committed to general aviation and provides high quality maintenance at a fair price.
The first surprise came a few days later, Marshall Aerospace said they could not repair the part as skins are not available and, legally, they are not allowed to reverse engineer any aircraft parts. This did not make sense to me. Marshall converts airliners, stretches, and modifies them, yet they cannot cut a piece ofaluminum for a Piper Comanche? If they can't, who can?
A friend drew my attention to the FAA FAR 21.303 (b)(2). He said that it allows an owner to reproduce his own replacement parts to be used in his aircraft (see http://www.access.gpo.gov/nara/cfr/cfrhtml_00/Title_14/14cfr21_00.html). I checked the FAR and found paragraph 21.203 (b)(2) to say as follows: "…. parts produced by an owner or operator for maintaining or altering his own product." I called Marshall to talk it over. The problem was with the wording, "…altering his own product". What is "his own product?" How is it defined? Is my Comanche my "own product?" Marshall and I came to the conclusion that we are not allowed to reproduce the part, the Comanche is not my "own product"; it is my aircraft, but it is Piper's product.
Marshall, not being lazy, started to build a case. They wanted to argue with the FAA that it is just unreasonable to write off an aircraft because of a trim tab being unavailable. A fax was sent to Piper's agents in the UK asking for a price and availability of the part. Days later we were told that the part is available, and we were offered a complete stabilator with no tabs, not what I needed. Apologies were said and more time was requested. They said, "We will have an answer within a week."
In the meantime, a friend who owns a Cessna 182, and had also suffered a bit of bad luck, heard about my problems and sent me a copy of the Cessna Pilots Association Magazine.
In an article by Mike Busch (volume 19, p. 28, June 2002), he claims that an owner can manufacture his own spare parts, and wrote, "As our aircraft get older, it's getting increasingly difficult to obtain replacement parts. They're often ridiculously expensive and sometimes downright unobtainable. Luckily, the FAA permits aircraft owners to fabricate their own parts. The regs on this subject are a bit cryptic and often misinterpreted, but important for aircraft owners and mechanics to understand."
He went on, saying, "The meaning of the second exception, "owner-produced parts" was rather murky until April 5, 1993, when Donald P. Byrne, the FAA's Assistant Chief Counsel for Regulations, issued a memorandum defining the term 'owner (or operator) produced part' as used in FAR 21.303 (b)(2). Byrne's memo clarifies the FAA's interpretation of the owner-produced parts exception, and as you'll see, that interpretation is surprisingly generous and liberal.
The Assistant Chief Counsel explained that it is not necessary for the owner to actually manufacture the part himself in order for the part to be considered an "owner-produced part." The owner may contract with a mechanic, a repair station, or even a non-certificated individual or firm (e.g., a machine shop) to manufacture the part for him, provided that the owner "participated in controlling the design, manufacture or quality of the part." Byrne went on to explain that the FAA would deem the part to be owner-produced if the owner:
1. Provides the manufacturer with design or performance data from which to manufacture the part. This test would be met if the owner provides the manufacturer with the old part and asks that it be duplicated; or
2. provides materials to make the part; or
3. provides fabrication processes or assembly methods to be used in making the part; or
4. provides quality control procedures to be used in making the part; or
5. supervises the manufacture of the part."
In support of Mike Busch's article, a fellow Comanche pilot who participates in the Delphi Comanche Forum provided me with a link to another article that effectively said the same, i.e. that an owner can manufacture his own parts. (http://www.amtonline.com/searchscripts/search.asp?SearchSiteURL=\articles\ 2001\04-01\amt_04-01_12.htm)
Yet, Marshall and I still refused to believe it as the FAA is known to fight bogus parts, it just did not make sense to us that they would allow owners to produce there own.
In the meantime we received a polite fax from Piper. They were willing to help and to remanufacture the part, however, they would have to reproduce some of the necessary tooling. Cost? Well, they would like to have several tens of thousands of dollars, and our reply would be greatly appreciated. Together with the negative replies to our inquiries from many aircraft salvage yards, Piper's reply went into the file to prove that the aircraft is not supported by the manufacturer. We thought that with this evidence the FAA would permit Marshall to reverse engineer the part.
Marshall contacted the FAA inspector based in London to discuss the problem. It appeared that on the following day he was due to visit another department nearby and it was agreed that he would drop in to have a look. Our case, including all the correspondence, was put in front of him.
The inspector did not know about the "owner-produced part" route and promised to check it out with the New York FSDO when he would be there the following week. By now the aircraft had been grounded for 7 weeks and a solution to the problem seemed to be just as far away as before. Being a helpful type of inspector, he suggested we contact a salvage yard that we had not tried. He said they might have the part. The yard was White Industries Inc.
We called and asked, "Have you got a left hand stabilator trim tab for a PA24-260-C P/N…..?" "Yes, we do." was the answer; "We will email you photos within half an hour." The part looked perfect in the photos. A phone call confirmed that the part was not corroded and that if it was found to be unsatisfactory it could be returned. A week or so later the tab arrived at Marshall's facilities. It was inspected and was confirmed to be as described. We thought that by the next day it would be done and dusted, not so.
On the following day, when the aircraft was scheduled to be fitted with the newly acquired trim tab, the FAA inspector dropped in with answers regarding the "owner-produced part" questions. He was told that we were successful with White Industries and the trim tab was shown to him. He looked at it and asked, "How do you know that this trim tab is not a bogus part?" Our answer was, "You told us about it." He replied, "That's true, but how do you know that it is not a bogus part? There is no data plate on it."
The purchase invoice, stating the tail number of the aircraft that the part was removed from, was presented as well as an FAA aircraft registration search confirming that the aircraft was de-registered due to an accident. He was not convinced and wanted further proof that the part was a genuine part. The only way forward was to compare both parts.
Marshall carried out a non-destructive test to confirm that the correct gauge of aluminium was used and that both weigh the same and measure the same (all measurements and weights were identical or very close to each other). In the meantime I was on the line to Maurice Taylor, the ICS Technical Director, asking for help. In reply, Maurice wrote, "As long as I have been with Piper (since 1946), they have used the same system. There is only one data plate and it is never attached anywhere but on the fuselage; never on controls or any other parts. I don't know of a better way to indicate that the part came from an original certified Piper aircraft. This method is used every day throughout the US and I have every reason to believe it is very legal."
A further email arrived few days later, "Thanks for your letter. I talked with Piper this morning again about your problem and just like we have been talking, the trim tab would have been identified along with the other parts for that aircraft without any number being put on the part, so that all parts were accounted for."
A few days later the trim tab was on the aircraft and, at my request, the stabilator was re-balanced. Better to be safe than sorry. Another week had gone before I could collect the aircraft. The total down time was 9 long, frustrating weeks, but an important lesson was learned. We can legally manufacture parts for our own aircraft.
Thanks to all who have helped.
Ben Ayalon, born in Israel in 1955, studied aircraft engineering at Holtz Technical College in Tel Aviv. He served for 6 1/2 years in the Israel Air Force and later joined Israeli Aircraft Industries where he took part in the development of the "Lavi" fighter. In 1987, Ben moved to the UK to study and obtain a degree in Business Administration. There, he started his own computer business, and now owns a Comanche 260-C, based at Elstree, England (EGTR).